I see Russia calling a meeting to adopt a resolution on a conflict it had fuelled. Why did the rebels claim the resolution did not apply to Debaltseve? Why had Russia in Minsk II continued to arm the rebels in Donetsk and Luhansk, when this was a precondition before holding elections in Donbas? Why was the OSCE/ODIHR not respected by Russia? Why did Russia make further demands in May 2015?
As you seem to miss the importance and relevance of the Minsk 2 accords being adopted as a Security Council resolution, I will spell it out for you.
"The UNSC is the only UN body with the authority to issue binding resolutions on member states" Look it up yourself if you don't understand. It isn't the General Assembly, UNESCO, UNICEF- it has real legal authority. This is why it is the only UN body that doesn't use simple majority voting but allows a veto for the "Permanent 5". US/UK/France/Russia/China. Why would UK/US/FR not veto a resolution that you dismiss as "meeting called by Russia". Tell me that you know nothing about the working of the UN Security Council without telling me that you know nothing of the mechanisms of the UNSC.
Your first point requires you to ignore that the Ukrainian armed forces attacked the regions of Donetsk and Lugansk. It also requires the ignoring of public confessions by Merkel and Hollande that they had no intention of abiding by the Security Council resolution. This happened and is all a matter of record. Pretending that NATO and Ukraine are "innocent by-standers" is absurd. The US, UK and France all had the opportunity to veto the whole resolution. The acquiescence of US, UK and France to bring the vote and unanimously agree, no vetoes, also informs the answer to your other questions.
I have stated previously, some time ago, on this thread the reasons behind the acquiescence of US?UK/FR in the Security Council. Over a year ago now, from memory.
Anyway, a huge number of Ukrainian Army, and many NATO operatives(tut tut!) were trapped by separatist forces in a cauldron at Debaltseve. There only options were to surrender and be captured or die. The Russians and separatists used this leverage against NATO members UK/US/FR hence their acquiescence to Minsk 2 becoming a Security Council resolution.
The rebels felt deceived by having to release what were effectively captured soldiers knowing that they would return to fight again. Any Russian arming of rebels, especially given the admitted and documented use of Ukrainian military to quell their own citizens, would be legitimate self defence. Russia denied this however and no evidence has been shown to suggest any official arming of the rebels by Russia. Western arm sales and provision of them to various jihadi and rebel groups around the world(thousands of miles away) means that you don't get to feign offence anyway. We openly send billions of dollars of arms around the world to various groups attempting to overthrow sovereign governments.
Why don't you look up the reasons for the OSCE falling out of favour. The Russians are open about the reasons. Too much to summarise briefly. Lavrov has spoken extensively about it.
Russia didn't make extra demands in May 2015. Whatever this vague question refers to is with certainty some other lie that has been repeated often enough for you to believe without further question.